1. Field of the Invention
The present invention relates to a radiation detection technique and, more particularly, to a management apparatus and management method for managing a radiation detection apparatus capable of capturing a radiation image without exchanging synchronization signals with a radiation generating apparatus, and a non-transitory computer-readable storage medium.
2. Description of the Related Art
Recently, the digitization of radiation images has been promoted in a medical field, leading to many merits. For example, it is possible to speed up diagnosis by allowing a user to quickly check captured images on a display device or the like upon digital transmission to it. In addition, digitization improves diagnosis accuracy with respect to a fine lesion as well as automating diagnosis by various types of image processing. Furthermore, since there is no need to secure a film storage space, the space efficiency inside a hospital greatly improves. Moreover, since digital transmission hardly suffers data deterioration, it is possible to transmit captured images to a remote place without any deterioration. By making the most of these features, diagnosis can be received from a highly trained doctor by transmitting images captured in a home care site, a disaster site, or the like to a fully equipped urban hospital.
Radiation detection apparatuses have been commercially available and rapidly popular, which use a digital radiation imaging method of forming an image by converting radiation into an electric signal by using a plurality of radiation detection elements arrayed in a two-dimensional matrix instead of a film. As a radiation detection apparatus of this type, a radiation detection apparatus using an FPD (Flat Panel Detector) has been proposed. In such a radiation detection apparatus, minute radiation detectors, each obtained by stacking a solid-state photoelectric conversion element and a scintillator for converting radiation into visible light, are arranged as image sensing elements in a two-dimensional matrix. Each image sensing element converts irradiated radiation into an electric signal (charge amount) corresponding to the irradiation dose. In general, an FPD can accumulate charges generated by irradiation with radiation in solid-state photoelectric conversion elements by controlling a voltage to be applied to the elements. Then, the FPD reads out charges from the solid-state photoelectric conversion elements by controlling the voltage to be applied to the elements to be another voltage, and forms image data in accordance with the accumulated charge amounts.
When capturing a radiation image by using the FPD, the timing of irradiation with radiation and the timing to perform accumulation (imaging) of charges in the radiation detection apparatus need to be accurately synchronized with each other in consideration of the characteristics of solid-state photoelectric conversion elements in use. For this purpose, there is proposed a radiation imaging system which synchronizes the radiation irradiation timing and the imaging timing by exchanging synchronization signals between the radiation generating apparatus and the FPD, as disclosed in, for example, Japanese Patent No. 4684747. More specifically, the FPD makes preparation for imaging in response to an irradiation request signal from the radiation generating apparatus. Then, an irradiation permission signal is transmitted to the radiation generating apparatus in accordance with the start of imaging by the FPD (the start of accumulating charges), thereby performing irradiation with radiation. In a radiation imaging system proposed in Japanese Patent Laid-Open No. 11-155847, the FPD detects the radiation irradiation timing by detecting a change of a current caused inside upon irradiation with radiation. The FPD starts imaging in response to the detection as a trigger, thereby establishing synchronization between the radiation irradiation timing and the imaging timing.
In a system in which the radiation generating apparatus and the FPD exchange synchronization signals, as disclosed in Japanese Patent No. 4684747, the radiation generating apparatus and the FPD need to be connected in electrically one-to-one correspondence. This puts a constraint on system building such that the radiation generating apparatus and the FPD require connection interfaces. Further, in a system as disclosed in Japanese Patent No. 4684747, a conventional radiation generating apparatus not coping with the FPD does not have a connection interface and suffers problems such as incapability of imaging by the FPD.
In the radiation imaging system described in Japanese Patent Laid-Open No. 11-155847, the radiation detection apparatus itself detects irradiation with radiation and performs imaging. This system can therefore solve problems arising from the necessity of an electric connection with the radiation generating apparatus. Since no additional apparatus or the like need be connected, the system is satisfactorily flexible. However, the following problems may arise.
In a radiation imaging system in which a radiation generating apparatus and a radiation detection apparatus are not synchronized with each other, the radiation generating apparatus can generate radiation regardless of the state of the radiation detection apparatus and the state of an imaging control apparatus which controls the radiation detection apparatus and displays and saves an image. When irradiation with radiation is performed in a state in which the radiation detection apparatus is not ready yet, a case (first case) is conceivable, in which an obtained image becomes a poor image under the influence of charges remaining in the radiation detection apparatus or the like, and no effective image can be obtained. Also, when irradiation with radiation is performed in a state in which the imaging control apparatus is not ready yet, a case (second case) is also conceivable, in which even if the radiation detection apparatus obtains an effective image, the imaging control apparatus is not ready for controlling the radiation detection apparatus and the image can be neither displayed nor saved. Further, when irradiation with radiation is performed in a state in which the imaging control apparatus has not prepared patient information and examination information, a case (third case) is also conceivable, in which even if the radiation control apparatus obtains an image from the radiation detection apparatus, it cannot appropriately associate the image with patient information and examination information. Re-imaging is necessary in all these cases, causing a problem because ineffective exposure to a patent may be performed.
There is a need for an imaging system in which when the state is improper, as described above, and imaging is performed in spite of mis-exposure, the user is quickly notified of the mis-exposure to stop irradiation by the radiation generating apparatus and make a notification to request re-imaging or the like.